This pattern is most often observed in underdeveloped countries where individuals do not live to old age because of less-than-optimal living conditions. Countries with rapid growth have a pyramidal shape in their age structure diagrams, showing a preponderance of younger individuals, many of whom are of reproductive age or will be soon ( ). Age structure allows better prediction of population growth, plus the ability to associate this growth with the level of economic development in the region. Age structure is the proportion of a population at different age ranges. The age structure of a population is an important factor in population dynamics. Age Structure, Population Growth, and Economic Development Thus, it appears that the influence of infectious disease on human population growth is becoming less significant. To compare to some of the epidemics of the past, the percentage of the world’s population killed between 19 decreased from 0.30 percent of the world’s population to 0.24 percent. According to the World Health Organization, global death from infectious disease declined from 16.4 million in 1993 to 14.7 million in 1992. Today, the threat of infectious disease, while not gone, is certainly less severe. In the past, diseases such as the bubonic plaque of the fourteenth century killed between 30 and 60 percent of Europe’s population and reduced the overall world population by as many as 100 million people. Public health, sanitation, and the use of antibiotics and vaccines have decreased the ability of infectious disease to limit human population growth. Humans originated in Africa, but have since migrated to nearly all inhabitable land on the Earth. Other factors in human population growth are migration and public health. In addition, humans use language to communicate this technology to new generations, allowing them to improve upon previous accomplishments. Humans can construct shelter to protect them from the elements and have developed agriculture and domesticated animals to increase their food supplies. Much of this ability is related to human intelligence, society, and communication. This ability is a major factor responsible for human population growth and a way of overcoming density-dependent growth regulation. ![]() Humans are unique in their ability to alter their environment with the conscious purpose of increasing its carrying capacity. In spite of this fact, human population is still growing exponentially.Ĭlick through this interactive view of how human populations have changed over time. Also, resources would have to be such that the environment would support such growth. To reach its biotic potential, all females would have to become pregnant every nine months or so during their reproductive years. The world’s human population is currently experiencing exponential growth even though human reproduction is far below its biotic potential ( ). As some point out, it is likely that the negative effects of increasing carrying capacity will outweigh the positive ones-the carrying capacity of the world for human beings might actually decrease. The ultimate effect of these changes on our carrying capacity is unknown. The depletion of the ozone layer, erosion due to acid rain, and damage from global climate change are caused by human activities. ![]() Earth’s human population is growing rapidly, to the extent that some worry about the ability of the earth’s environment to sustain this population, as long-term exponential growth carries the potential risks of famine, disease, and large-scale death.Īlthough humans have increased the carrying capacity of their environment, the technologies used to achieve this transformation have caused unprecedented changes to Earth’s environment, altering ecosystems to the point where some may be in danger of collapse. Humans, however, have the ability to alter their environment to increase its carrying capacity sometimes to the detriment of other species (e.g., via artificial selection for crops that have a higher yield). For example, beaver dams alter the stream environment where they are built. Humans are not unique in their ability to alter their environment. Discuss the long-term implications of unchecked human population growthĬoncepts of animal population dynamics can be applied to human population growth.Relate population growth and age structure to the level of economic development in different countries.Explain how humans have expanded the carrying capacity of their habitat. ![]() Discuss how human population growth can be exponential.By the end of this section, you will be able to:
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